基于qPCR和16S rDNA高通量测序研究蓝藻暴发期间太湖竺山湾水体浮游细菌群落

为了探究浮游细菌和蓝藻暴发之间的关系,利用实时荧光定量PCR和高通量测序技术,对夏季蓝藻暴发期间太湖竺山湾表层水和底泥中浮游细菌群落结构和多样性进行研究。结果表明,从门水平来看,水样和底泥中平均相对丰度最高的为变形菌门,放线菌门次之,此外蓝藻门也有一定的比例,可为水华暴发提供预警指示;从属水平来看,水样中的优势细菌主要为GpXI和GpIIa,底泥中为Gp6和GpIIa。     

一株芘降解菌B2的降解条件优化及降解基因

芳香烃降解菌是石油污染土壤修复的主要生物资源。采用芘平板升华法对克拉玛依原油污染土壤样品进行驯化培养,分离得到一株芘降解菌B2,经16S rDNA基因序列比对及系统发育进化分析表明,该菌株为假单胞菌属(Pseudo-monas)。采用正交设计方法优化菌株B2对高分子量多环芳烃芘的降解条件,并构建多元非线性模型预测菌株B2对芘的最佳降解条件,结果表明:在接种量OD660 nm为0.60、降解温度为40℃、降解时间为6.0 d时,预测菌株B2对芘的降解最大达到38.214 mg/L,实际测得最大降解量为37.906 mg/L,预测准确率为99.19%。运用PCR技术克隆B2的邻苯二酚-2,3-双加氧酶基因(B2C23O)(I.2.A亚家族),核酸序列分析表明,该基因全长880 bp,具有一个完整的开放阅读框,编码246个氨基酸,与已报道的Pseudomonas putida W619同源性最高为97%;对B2C23O基因编码氨基酸序列进行分析,发现其具有邻位断裂双加氧酶模式结构,推测菌株B2通过邻位裂解途径降解芘代谢中间产物邻苯二酚。     

植物床-沟壕系统的藻类捕获功能

采用原位实验验证植物床．沟壕系统的藻类捕获功能。结果表明：该系统能够有效拦截和捕获源水藻类。在水力梯度驱动下,约35％源水进入高位小沟流经植物床内部根孔结构而汇至低位小沟。低位小沟内叶绿素a（Chl-a）浓度显著低于高位小沟（P=0．0239）,其降低比例为11．1％。以植物床．沟壕系统为结构形式的根孔净化区其出水Chl-a浓度较源水整体下降了27．0％。估算该片根孔净化区捕获藻类鲜生物量约122kg／d。石臼漾湿地共含根孔净化区11片,按供水25万t／d计,估算捕获藻类鲜生物量约1100kg／d。     

Geofractionation of heavy metals and application of indices for pollution prediction in paddy field soil of Tumpat, Malaysia

The present study investigates the concentration of Pb, Cd, Ni, Zn, and Cu in the paddy field soils collected from Tumpat, Kelantan. Soil samples were treated with sequential extraction to distinguish the anthropogenic and lithogenic origin of Pb, Cd, Ni, Zn, and Cu. ELFE and oxidizable-organic fractions were detected as the lowest accumulation of Pb, Cd, Ni, Zn, and Cu. Therefore, all the heavy metals examined were concentrated, particularly in resistant fraction, indicating that those heavy metals occurred and accumulated in an unavailable form. The utilization of agrochemical fertilizers and pesticides might not elevate the levels of heavy metals in the paddy field soils. In comparison, the enrichment factor and geoaccumulation index for Pb, Cd, Ni, Zn, and Cu suggest that these heavy metals have the potential to cause environmental risk, although they present abundance in resistant fraction. Therefore, a complete study should be conducted based on the paddy cycle, which in turn could provide a clear picture of heavy metals distribution in the paddy field soils.     

Boron sorption from aqueous solution by hydrotalcite and its preliminary application in geothermal water deboronation

Hydrotalcite and its calcination product were used to treat pure water spiked with various concentrations of boron and geothermal water containing boron as a major undesirable element. The kinetics process of boron sorption by uncalcined hydrotalcite is controlled by the diffusion of boron from bulk solution to sorbent-solution boundary film and its exchange with interlayer chloride of hydrotalcite, whereas the removal rate of boron by calcined hydrotalcite rests with the restoration process of its layered structure. The results of isotherm sorption experiments reveal that calcined hydrotalcite generally has much stronger ability to lower solution boron concentration than uncalcined hydrotalcite. The combination of adsorption of boron on the residue of MgO–Al₂O₃ solid solution and intercalation of boron into the reconstructed hydrotalcite structure due to “structural memory effect” is the basic mechanism based on which the greater boron removal by calcined hydrotalcite was achieved. As 15 geothermal water samples were used to test the deboronation ability of calcined hydrotalcite at 65 °C, much lower boron removal efficiencies were observed. The competitive sorption of the other anions in geothermal water, such as HCO₃ ^?, SO₄ ^2?, and F^?, is the reason why calcined hydrotalcite could not remove boron from geothermal water as effectively as from pure boron solution. However, boron removal percents ranging from 89.3 to 99.0 % could be obtained if 50 times of sorbent were added to the geothermal water samples. Calcined hydrotalcite is a good candidate for deboronation of geothermal water.     

十溴联苯醚共存条件下水中Zn(Ⅱ)的生物吸附

研究了十溴联苯醚(BDE-209)共存条件下嗜麦芽窄食单胞菌对水中Zn2+的吸附特性,并通过对菌体进行失活处理、红外光谱和X-光电子能谱分析,探讨了吸附机理。结果表明,Zn2+的吸附符合Freundlich吸附模式;嗜麦芽窄食单胞菌对Zn2+吸附作用明显,2.5 g/L菌体在2 h时,对初始浓度为2.0 mg/L Zn2+的去除率达92%。BDE-209对菌体吸附Zn2+有一定的抑制作用。各因素对嗜麦芽窄食单胞菌吸附Zn2+的影响程度由大到小依次为:投菌量>pH>BDE-209浓度。菌体对Zn2+的吸附除表面吸附外,还存在跨细胞壁细胞膜的主动运输和积累等作用。菌体中的酰胺基与羟基均参与了Zn2+吸附,而且菌体表面Ca2+与Zn2+发生了离子交换,吸附后Zn2+的价态不变。     

8种植物床人工湿地脱氮除磷的研究

分别以水葫芦、西洋芹、空心菜、水芹、混合种(黄菖蒲、千屈菜、再力花)、千屈菜、再力花、黄菖蒲等植物床构建潜流人工湿地,研究其对生活污水氮、磷的净化功能及其去除率与水力停留时间(HRT)的变化规律。结果表明,各种植物床对TN、TP的去除率随HRT的延长而增加,不同植物床的脱氮除磷效果是不同的。千屈菜植物床对TN的去除效果最好,HRT为3d时,TN去除率为56%;HRT为6d时,TN去除率达77%。再力花植物床对TP的去除效果最好,HRT为3d时,TP去除率达78%;HRT为6d时,TP去除率达96%。其他植物床也有较好的脱氮除磷效果。各种植物床处理后出水TN、TP均较低,HRT为3d时,出水TN均低于《城镇污水处理厂污染物排放标准》(GB 18918—2002)一级A标准规定的限值(15mg/L),出水TP均低于GB 18918—2002二级标准规定的限值(3mg/L);7种植物床构建的潜流人工湿地(水葫芦的数据丢失)对TN、TP的去除均满足一级反应动力学方程,且相关性显著。     

Polyfluorinated compounds in the atmosphere along a cruise pathway from the Japan Sea to the Arctic Ocean

Neutral polyfluorinated alkyl substances (PFASs) were measured in high-volume air samples collected on board the research vessel Snow Dragon during the 4th Chinese National Arctic Expedition from the Japan Sea to the Arctic Ocean in 2010. Four volatile and semi-volatile PFASs (fluorotelomer alcohols (FTOHs), fluorotelomer acids (FTAs), perfluoroalkyl sulfonamides (FASAs), and sulfonamidoethanols (FASEs)) were analyzed respectively in the gas and particle phases. FTOHs were the dominant PFASs in the gas phase (61-358 pg m⁻³), followed by FTAs (5.2-47.9 pg m⁻³), FASEs (1.9-15.0 pg m⁻³), and FASAs (0.5-2.1 pg m⁻³). In the particle phase, the dominant PFAS class was FTOHs (1.0-9.9 pg m⁻³). The particle-associated fraction followed the general trend of FASEs > FASAs > FTOHs. Compared with other atmospheric PFAS measurements, the ranges of concentrations of ∑FTOH in this study were similar to those reported from Toronto, north America (urban), the northeast Atlantic Ocean, and northern Germany. Significant correlations between FASEs in the gas phase and ambient air temperature indicate that cold surfaces such as sea-ice, snowpack, and surface seawater influence atmospheric FASEs.     

南苕溪支流锦溪水质时空变化特征分析

综合运用灰色聚类法、综合污染指数法、等级聚类法就南苕溪支流锦溪近年水质时空变化特征进行分析。结果表明,锦溪入青山水库断面水质2005—2009年逐年改善,2007年后达到灰色聚类等级Ⅲ类水质要求;2009年秋季至2010年夏季期间秋、冬两季的污染程度高于春、夏季节;枯水期综合污染指数最高,但TN、TP污染分指数在丰水期最高,表明污染源中面源污染已占相当比例。空间变化方面从玲珑桥到江桥锦溪水质的综合污染指数不断提升,到江桥时达到极值13.25,锦溪末端三眼桥断面水质较江桥断面有所改善;SPSS空间聚类分析可分为轻污染区(从玲珑桥到冬韵桥)、重污染区(从群利桥到江桥)和中度污染区(从江桥到三眼桥)。锦溪上游农业区对河水中的COD、TN和TP的贡献率分别为66%、54%和49%,农业面源污染已成为制约锦溪水质改善的主要因素。     

利用多年期赤泥和煤矸石制备烧结砖

以多年期赤泥和煤矸石为主要原料,分析了其化学成分和物性特征,通过设计不同的原料配比和烧结温度,探讨其最佳工艺条件以及各种参数指标,试图为赤泥的大宗化利用提供一种新的途径。实验结果表明最佳工艺条件为:多年期赤泥与煤矸石质量比为20∶80,成型压力为6 MPa,烧结温度为1 100℃左右保温2 h。烧结砖体"泛霜"现象基本消失,抗压强度为12.18 MPa、吸水率为21.6%,满足国家粉煤灰普通烧结砖GB5101-2003中的要求。